Jackson (knee) is listed as questionable for Sunday's game against the Cardinals, Adam Grosbard of The Orange County Register reports.
Jackson was limited by a knee injury all week during practice and has a chance to return from a one-game absence. The Rams intend to play their starters Sunday despite being limited to the fifth or sixth seed for the NFC playoffs, but if Jackson is ultimately ruled out, then D.J. Humphries would likely remain as the team's starting left tackle.